Recompress all large JPGs to reduce repo size

[bstrand]

Partial fix for #190

NB To realize the reduction in repo size, strip the old blobs from the history with filter-repo.

Image file size reduction

• Target: JPEG files larger than 2 MB
• No images were deleted or resized; only recompressed
• Recompression was done with ImageMagick with the following parameters:
  magick "$jpg_file" -strip -interlace Plane -sampling-factor 4:2:0 -quality 33%

Results

• .jpg file sizes reduced by 90%
• Repo disk usage reduced by 267 MB (504 -> 237)
• Repo still large due to old files in git history

Before:

code_snippets on master✔ » du -h -d 1 . | sort -rh | head -n5
504M	.
318M	./Python
161M	./.git
 24M	./Django_Blog
 28K	./Terminal

After:

code_snippets  on 190-recompress-large-jpgs✔» du -h -d 1 . | sort -rh | head -n5
237M	.
176M	./.git
 50M	./Python
 11M	./Django_Blog
 28K	./Terminal

Follow-up: filter large blobs

To realize the reduction in repo size, strip the old blobs from the history with filter-repo. Following this guide and using a max blob size of 2M:
git filter-repo --strip-blobs-bigger-than 2M

Results of doing the above on my fork of code_snippets repo

• Repo download (clone) reduced to 17 MB (down from 164 MB)
• Repo total disk usage reduced to 69 MB (down from 504 MB)

Clone before:
Receiving objects: 100% (940/940), 163.91 MiB | 9.24 MiB/s, done
Clone after:
Receiving objects: 100% (923/923), 16.68 MiB | 7.64 MiB/s, done.

Before:

code_snippets on master✔ » du -h -d 1 . | sort -rh | head -n5
504M	.
318M	./Python
161M	./.git
 24M	./Django_Blog
 28K	./Terminal

After:

code_snippets on master✔ » du -h -d 1 . | sort -rh | head -n5
 69M	.
 40M	./Python
 18M	./.git
 11M	./Django_Blog
 28K	./Terminal